bike culture blogged

Note: I have a special spam folder for the occasional gems like this from Taiwan

Power-curved cranks use the design of golden spiral ratio, which create more pedaling efficiency than traditional cranks can provide, so that no matter bike lovers or normal riders can enjoy more fun of speed and comfortable riding.

BioPace redux. Anyone going to the Taipei Bike Show please investigate further. Totally pimp to put a pair of those on a cargo bike.

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15 Comments

Byron and I were chatting about this back-channel. Obviously, these will have ZERO effect on your pedal stroke, because the distance from crank center to pedal spindle center will never change, and they’ll have ZERO effect on the effort going to the powertrain because they’re just a spider, so they don’t change the mechanical advantage of the chainrings.

But I cracked on Byron for calling them “BioPace redux”: I used to have a commute and rain-bike Centurion with late Biopace rings, which were an offering from Shimano that used slightly oval chainrings to attempt to give the rider more mechanical advantage at the weaker part of the pedal stroke.

I never really thought enough for or against them to swap them out, especially on a beater bike. My “nice bike” was slightly lower geared (maybe a 52 x 39 vs. 53-42?), but I noticed I could push a (slightly!) higher gear on the same climb on the Centurion. Your Mileage May Vary, but that was my experience, that’s my story, and I’m sticking to it.

Shimano gave up on the experiment pretty quickly, but Bobby Julich continued to ride Biopace-like rings until he retired.

Like cords being in fashion, these no dead spot cranks come and go. Tales are still told of the PowerCranks, where we thought that was going to improve our pedal stroke and all it did was make us really good at PowerCranking and less good at regular cranking.

> The marketers of Biopace made a crucial error of judgement: too much information.

I never said they were an engineering failure. Shimano does their homework, but they also market products like Biopace or more recently Coasting. Biopace was a marketing failure and my note that said, Biopace redux was saying, “here we go again with another crankset that address the deadspot.”